An overwhelming majority of conventional door locks may be opened through a hand to turn the handle of lock or a key to open the heart of lock, so that the tongue of lock is retracted to disengage from the catch on the door frame. However, these conventional door locks are considerably inconvenient for some people or in some circumstances. For instance:
1. The people who suffer apoplexy or broken arms cannot use their arm strength or have no arms to use, so they always cannot open the rotary door lock in general and the most popular trumpet lock in particular. If they leave from or enter into the room, they have to wait for someone else coming to open the door lock for them; otherwise, they cannot unlock it, this is extremely inconvenient for them.
2. When we carry a heavy object or hold something with two hands and intend to pass through or enter into the door equipped with the said lock, since these two hands are occupied and thus cannot open the door, so we have to put down the said heavy object or something on the floor in order to use a hand to turn the handle or heart of lock, then we may carry the heavy object or something to pass through the door. This is extremely troublesome and inconvenient for the people at large who complain about it very much.
In view of the above, the present inventor, through his research and development, invented a "push-pull door lock" of the present invention which can fully eliminate the foregoing drawbacks of conventional locks.